\section{Results and Discussion}
\label{sec:results}
The program features a GUI that can be used without a keyboard. It has been
tested with a mouse and a touch screen, which are both very usable.

The source code is hosted at \texttt{massy.googlecode.com} and can be obtained
by typing \texttt{hg clone https://massy.googlecode.com/hg/ massy}.\\

\noindent Use the \texttt{make} command to compile the source code and to
create an executable.

\subsection{Discussion} % {{{
\label{sub:discussion}
We initially planned to implement the AI for the detectives instead of Mr. X.,
but since time was short and making a policy for Mr. X. still proved
sufficiently challenging, we decided against it.

\subsubsection{Path Planning} % {{{
\label{ssub:path}
Originally we intended to use the $A^*$ algorithm for path-planning, but since
the physical distance between hardly relates to the real cost (which we wanted
to base on several factors such as available tickets and number of steps),
there was no good heuristic to use.

An alternative would be Dijkstra's algorithm as it does not need a heuristic
and can find the shortest path in $O(n \log n)$.

Eventually we decided against path-planning because only the nodes very close
to Mr. X. are relevant to escaping the detectives.
% subsubsection path }}}

\subsubsection{Features} % {{{
\label{ssub:feats}
The current AI does not yet use the ``black tickets'' and ``2X tickets''.
% subsubsection feats }}}

\subsubsection{Improvement: Stochastic Policy} % {{{
\label{ssub:stochastic}
The AI could be improved by using a stochastic policy. Since the current policy
is entirely deterministic, it is possible for the players to know exactly which
action Mr. X. will take.
% subsubsection stochastic }}}

% subsection discussion }}}
